Continuity mistake: When Opie and Arnold rush into the house and tell Andy and Aunt Bee about the party, in the shots facing the boys we can see the reflection in the mirror behind them, and there's a lamp atop the credenza, but in the shots facing Andy and Aunt Bee that lamp doesn't exist.
Factual error: Goober and the Taylors stop and get gas in Raleigh before heading back to Mayberry. As they are waiting, a Coors Brewing Company truck is seen driving past the service station. Coors Beer was not sold east of the Mississippi River until the mid-1980s.
Visible crew/equipment: When Andy gets back from Raleigh and shuts the car door, just as the camera moves in closer we can see the reflections of two crew members (the one wearing a yellowish shirt looks as if he's pushing the camera dolly), on the window behind Andy.
Continuity mistake: When Andy finds the old newspaper clipping in Helen's box he tucks it into his pocket, but when he's looking at the clipping while he's at the office the newsprint on the back is entirely different. Then when Howard reads it the newsprint changes yet again.
Continuity mistake: When Aunt Bee picks up Opie at Billy's house, she parks the car in front and walks up to the front door. In the wideshot there's a space of approximately 3-4 feet between the blue window shutter and the door trim under the pediment, but in Aunt Bee's closeup there is no space whatsoever.
Continuity mistake: In the scene where the meeting participants are in the kitchen, the Russian guy opens the icebox, does not close it, and sits at the table. When Aunt Bee comes in immediately thereafter, the door is closed. She opens it again and partially closes it; but in the next shot, it is fully open.
Visible crew/equipment: After the shot of Milly holding hands with Howard (holding a picnic basket), when it cuts to Goober sitting in front of the courthouse the camera angle is low, so the wood framework and lighting equipment at the top of the courthouse set is visible, just as Andy walks over to Goober. (00:05:30)
Other mistake: During the scenes at Elmo's shop, where Aunt Bee's pictures are developed, it's obvious that this is actually Emmett's Fix-It Shop. We can see the window of the shop next door through Elmo's doorway, and recognize it as the store next door to Emmett's shop which has "Furniture, New and Used" on its front window.
Visible crew/equipment: After Andy hatches the plan to have Aunt Bee and her friends pick up their photos at the same time, in the following shot just as Andy walks into the shop, the shadow of the boom mic is moving beside the doorway, at the top left side of the screen.